Iron-Binder Polycrystalline Diamond for Cobalt-Free Sintering

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Solution Overview

Problem

The use of tungsten and cobalt, classified as Critical Raw Materials, in polycrystalline diamond (PCD) production poses challenges due to supply risks and lack of substitutes, necessitating the development of alternative materials for extreme conditions like rock removal and machining operations.

Innovation Solution

A method involving a precursor binder mixture of Fe x N and graphite powders is used to form a polycrystalline diamond body, replacing traditional cobalt and enabling sintering at high pressures and temperatures to create a viable alternative for PCD production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cobalt is used as a binder in PCD production, then the PCD body achieves adequate catalytic activity for diamond growth, but the supply reliability deteriorates due to cobalt being classified as a Critical Raw Material

Engineering Contradiction:
Improvesupply reliabilityVSAvoidcatalytic activity
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention changes the chemical composition parameters of the binder by replacing cobalt with iron nitride (Fe_xN) and graphite in specific weight ratios. This parameter change maintains the catalytic function while eliminating dependence on critical raw materials, thereby improving supply reliability without sacrificing catalytic activity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite binder system consisting of iron nitride and graphite together, or in combination with reduced cobalt content. This composite approach creates a new material system that achieves the required catalytic properties through synergistic effects, replacing the single-component cobalt binder and resolving the supply reliability issue

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If traditional cobalt binder is used, then the manufacturing process is well-established, but the sustainability deteriorates due to lack of viable substitutes for critical raw materials

Engineering Contradiction:
Improvemanufacturing process maturityVSAvoidsustainability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention modifies the binder composition parameters by introducing iron nitride and graphite while reducing or eliminating cobalt. The specific weight ratios (5-30 wt% Fe_xN, 5-30 wt% graphite) are optimized to maintain manufacturability while achieving sustainability goals through substitution of critical raw materials

Inventive Principle:
Principle #35Parameter changes

3Reliability

If cobalt content is reduced or eliminated, then the sustainability improves, but the catalytic activity for diamond growth may deteriorate

Engineering Contradiction:
ImprovesustainabilityVSAvoidcatalytic activity
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention creates a functional copy of cobalt's catalytic role using iron nitride and graphite. This substitute binder system replicates the essential catalytic function that enables diamond growth, allowing sustainability improvement without compromising the fundamental diamond formation process

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The composite of iron nitride and graphite works synergistically to provide the catalytic activity previously supplied by cobalt. The combination of these materials creates a new catalytic system that maintains diamond growth capability while eliminating dependence on critical raw materials

Inventive Principle:
Principle #40Composite materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The Fe x N and graphite catalysts successfully produce PCD bodies that perform comparably to conventional Co-PCD, reducing cobalt usage and offering a sustainable alternative for extreme tooling applications like rock removal and machining.

Implementation Method 1

The Fe x N and graphite are used as a catalyst for diamond growth

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 2

Sintering the green body at a temperature of 1700 °C to 2300 °C and at a pressure of at least 7 GPa, for at least 30 seconds to form a sintered PCD body

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP4021868B1Polycrystalline diamond with iron-containing binder
Publication Date: 2024.01.03 ELEMENT SIX (UK) LTD
  • EP4021868B1 patent drawingFigure 1~2
  • EP4021868B1 patent drawingFigure 3~4
  • EP4021868B1 patent drawingFigure 5~6

AI summary

This disclosure relates to a polycrystalline diamond (PCD) body comprising a PCD material formed of intergrown diamond grains forming a diamond network, and an iron-containing binder.